Since I've installed a complete clean installation of MacOS Sierra 10.12.3 Photo Mechanic build 18040 keeps on disappearing from my Dock. Every time I put it in there, the next time I reboot my mac, I see a question mark which says Photo Mechanic if I put my mouse pointer above it, but it doesn't open when I click it.

Since I've installed a complete clean installation of MacOS Sierra 10.12.3 Photo Mechanic build 18040 keeps on disappearing from my Dock. Every time I put it in there, the next time I reboot my mac, I see a question mark which says Photo Mechanic if I put my mouse pointer above it, but it doesn't open when I click it.

Any suggestions?

No. It appears to be a bug in macOS Sierra. PM does not communicate with the Dock to remove itself or to attempt to keep itself in the Dock. PM doesn't even "know" it is in the Dock.

Here is a thread where this problem was investigated and discussed in great detail:

Thank you all for your replies. Let's hope Apple will fix this issue. Strange that it isn't the same problem for everybody. I also did a clean install, but this was the result. Photo mechanic isn't the only program which gives me problems. Unfortunately, the problems I got with my Adobe CS5 are way bigger, and they just don't support it anymore. But I got the feeling that also with Adobe, not everybody is experiencing these problems, so it might be either a hardware issue, or something that is more or less apple ID related. Can it also be that the issue can also be caused by other installed programs, even when they are not running? Some kind of conflict?

Thank you all for your replies. Let's hope Apple will fix this issue. Strange that it isn't the same problem for everybody. I also did a clean install, but this was the result. Photo mechanic isn't the only program which gives me problems. Unfortunately, the problems I got with my Adobe CS5 are way bigger, and they just don't support it anymore. But I got the feeling that also with Adobe, not everybody is experiencing these problems, so it might be either a hardware issue, or something that is more or less apple ID related. Can it also be that the issue can also be caused by other installed programs, even when they are not running? Some kind of conflict?

It's hard to know but most apps on macOS don't have installers that modify how the system works.

I have had this problem too, this last month ever since a series of clean Sierra installs on a new 2016 Macbook Pro. PM Dock icon not working or being replaced by a question mark.

Additionally, when I opened PM, Little Snitch would ask if I want to allow outgoing connections. I said yes, any port, forever. But then later it would ask me again the next time I launched. It turns out over the last few weeks Little Snitch has churned out a dozen different rules allowing the exact same PM access. All became instantly invalid, all say something like:

Frankly, this is the first time ive ever heard of "app translocation," but Google says there are other apps similarly affected by this new system security feature in Sierra. The problem is that Sierra considers it un-safe to initially open a new app from a .dmg, the Downloads folder, a DVD, another computer (probly what I did) -- anything except for dragging the app directly into the Applications folder and launching from there. So I dragged a fresh copy of the Photo Mechanic 5.app over from the original .dmg and started it from the Applications folder. And so far so good - the PM icon now remains in the dock, totally functional, even after a computer restart. WOOFHOO.

The above fix is more thorough, but a quick workaround that I also tried was to nest the PM app inside another folder, any name, inside the Applications folder. Same positive results.